Andrea Bargnani spent 37 minutes showing his former team what they had seen for seven seasons.

Bargnani opened Friday night’s game against the Raptors looking like the sweet-shooting lottery pick who could spark an offense and control the glass, but the big man spent the second half of the Knicks’ 95-83 loss looking like the tentative, defensive liability that earned him a one-way ticket out of Toronto after last season.

With Carmelo Anthony out for the second straight game, Bargnani displayed much-needed aggression and asserted himself from the outset, putting up 14 points, nine rebounds and two blocks in the first half, but in the second half, the 7-footer disappeared, scoring only four points while shooting 1-of-5 from the field, and grabbing only three rebounds.

“I’m part of the team, so I played like the team played, very good in the first half, and in the second half, I’m not happy about it,” Bargnani said following the Knicks’ surrendering a 12-point second-half lead. “I don’t think it’s just one thing. It’s many things together. It’s focus, intensity, we didn’t have the same energy that we had in the first half. It’s a bunch of different things.”

After taking 12 shots in the first half, Bargnani seemed reluctant to create, as he had early on. He took only two shots in the fourth quarter and threw a late, costly turnover into the stands, with an open shot available.

“I wouldn’t call it tightening up,” coach Mike Woodson said, citing Bargnani’s two big buckets, late in Monday’s win against Orlando. “I wouldn’t call it that. If he had the shot, he’d take it. … I thought he had great looks in the third and fourth quarter, but he just didn’t knock them down.”

On Saturday, Bargnani will face his former team again, in a game unforgiving Toronto fans look forward to much more so than does the team’s much-maligned top pick of 2006.

It will be Bargnani’s regular-season return to his former home, but the big man knows what’s ahead of him, having been roundly booed in two preseason games.

“I’m going back to a place where I played seven years, but other than that, the team, the stuff, everything, everybody changes, there’s not even the people,” Bargnani. said “I don’t know anybody anymore, just a couple people, because they changed everybody.”

Well, not entirely. Former teammate Kyle Lowry is still in Toronto, for now at least.

The Knicks’ desired trade target earlier this month showed why he was so coveted on Friday, scoring 15 points with a season-high 11 assists.

At the team’s shootaround Friday morning, Lowry said he had heard some fans at the Garden chanted his name during the Knicks’ Christmas loss and was “humbled” by the recognition, but he wasn’t worried about when or if he would be dealt.

He said going against the Knicks didn’t feel any differently, even with all the deals that have been discussed.

It was just another game, a win for the Raptors. A win for the 12-15, first-place Raptors.

“At the end of the day I’ve got a Raptors uniform on, I wear No. 7, Toronto on the front, and we came here and got a win tonight,” Lowry said. “I made a commitment to the city of Toronto and to myself and to the fans to get the Raptors to the playoffs, so that’s what I’m here to do.

“We’ve got to take advantage of every opportunity we have to win games and that’s what we did. It’s very strange to be below .500 and lead your division, but we’ll take it.”